Apparatus for examining the eye are known in the art. The apparatus generally include a lens imaging module and a light sensitive apparatus, An example for such apparatus is the portable dynamic fundus instrument disclosed in U.S. Pat. No. 5,125,730 to Geraid et al.
This apparatus includes a video camera with an aspherical lens imaging module, designed to examine fundus blood vessels. One disadvantage of such apparatus is that they are incapable of covering a wide angle view of the fundus. Another disadvantage comes from their large physical dimensions which make the apparatus unsuitable for examining small eyes such as the eyes of a neonate and its retinal periphery. The original design of the optical unit uses a film camera technique.
Conventional wide angle optical units provide a wide angle view of the eye through an opening of the pupil of more than 2 mm in diameter. Such an opening can be achieved using special chemicals in the form of eye drops.
U.S. Pat. No. 5,007,729 discloses a wide angle ophthalmic lens utilizing aspherical optics, which is expensive and difficult to manufacture. Furthermore, this lens provides a curved imaging surface which is unsuitable for photographic purposes.
All of these apparatus require illumination. It will be appreciated that prior art illumination units are considerably large and require placing the examined eye in a fixed position, as disclosed in U.S. Pat. No. 4,200,362 to O. Pomerantzeff et al, for an ophthalmoscope with uniform illumination.